Battery pack

Abstract

A battery pack according to one aspect of the present technology is provided with batteries, and a heat absorbing member having a heat absorbing agent and a container that accommodates the heat absorbing agent. The heat absorbing member is disposed at a position adjacent to the batteries. The container is provided with a notch.

Description

Battery pack

[0001] The present technology relates to battery packs.

[0002] As electronic devices have become widespread, development of batteries as power sources for these devices has progressed. In this case, battery packs containing multiple batteries have been proposed to facilitate easy and safe handling of the batteries.

[0003] Various studies have been conducted on technologies related to the configuration of battery packs. For example, Patent Document 1 discloses a method in which a heat-absorbing member is brought into contact with a battery in a battery unit and the heat-absorbing member is used to cool the battery when it generates abnormal heat.

[0004] International Publication No. 2010 / 098067

[0005] However, in battery packs, depending on the arrangement and structure of the heat-absorbing member, it may be difficult to sufficiently cool a battery that has generated abnormal heat with the heat-absorbing member. It is desirable to provide a battery pack that can sufficiently cool a battery that has generated abnormal heat with the heat-absorbing member.

[0006] A battery pack according to a first aspect of the present technology includes a battery, a heat absorbing member having a heat absorbing agent and a container for accommodating the heat absorbing agent. The heat absorbing member is disposed adjacent to the battery. The container has a notch.

[0007] A battery pack according to a second aspect of the present technology includes a battery, a heat-absorbing agent, and a heat-absorbing member having a container that houses the heat-absorbing agent. The heat-absorbing member is disposed adjacent to the battery. The container has a housing that houses the heat-absorbing agent and a flange provided around the housing. The flange has a peelable portion that can be peeled off by heating to connect the housing space of the housing to the outside. The peelable portion has a narrow region where the width of the peelable portion is locally narrower than the width of the flange.

[0008] According to the battery pack of the first aspect of the present technology, a notch is provided in the container of the heat-absorbing member disposed adjacent to the battery, so that the heat-absorbing agent leaking to the outside through the notch can come into contact with the abnormally heated battery and cool the abnormally heated battery. Thus, by providing the notch in a desired location on the container, the abnormally heated battery can be effectively cooled. Therefore, the abnormally heated battery can be sufficiently cooled by the heat-absorbing member.

[0009] According to a battery pack according to a second aspect of the present technology, a flange portion of a container of a heat-absorbing member disposed adjacent to a battery is provided with a peelable portion that can be peeled off by heating to connect the storage space of the storage portion to the outside, and the peelable portion is provided with a narrow region in which the width of the peelable portion is locally narrower than the width of the flange portion. This causes the peelable portion to peel off due to the heat of an abnormally heated battery, allowing the heat-absorbing agent leaking from the container to come into contact with the abnormally heated battery and cool the abnormally heated battery. Thus, by providing the peelable portion at a desired location on the container, the abnormally heated battery can be effectively cooled. Therefore, the abnormally heated battery can be sufficiently cooled by the heat-absorbing member.

[0010] Note that the effects of the present technology are not necessarily limited to the effects described here, but may be any of a series of effects related to the present technology described below.

[0011] FIG. 1 is a diagram illustrating an example of a perspective configuration of a battery pack according to an embodiment of the present technology. FIG. 2 is a diagram illustrating an example of a perspective configuration of a battery module housed in the battery pack of FIG. 1. FIG. 3 is a diagram illustrating an example of an exploded perspective configuration of the battery pack of FIG. 1. FIG. 4 is a diagram illustrating an example of a cross-sectional configuration of the battery module of FIG. 2. FIG. 5 is a diagram illustrating an example of a perspective configuration of the heat absorption module of FIG. 4. FIG. 6(A) is a diagram illustrating an example of a perspective configuration of the heat absorption member of FIG. 5. FIGS. 6(B) and 6(C) are diagrams illustrating an example of a cross-sectional configuration of the heat absorption member of FIG. 6(A) taken along line A-A. FIGS. 7(A) and 7(B) are enlarged views illustrating an example of a cross-sectional configuration of a portion of FIG. 6(B). FIG. 8 is an enlarged view illustrating an example of a perspective configuration of a portion of the heat absorption member of FIG. 6(A). FIG. 9 is an enlarged view illustrating a cross section of a portion of the battery module of FIG. 2. FIG. 10 is a diagram illustrating an example of a manufacturing process of the heat absorption member of FIG. 6(B). FIG. 11(A) is a diagram showing a modified cross-sectional configuration of the heat-absorbing member of FIG. 7(A). FIG. 11(B) is a diagram showing a modified cross-sectional configuration of the heat-absorbing member of FIG. 7(B). FIG. 12(A) is a diagram showing a modified perspective configuration of the heat-absorbing member of FIG. 6(A). FIGS. 12(B) and 12(C) are diagrams showing an example cross-sectional configuration of the heat-absorbing member of FIG. 12(A) taken along line A-A. FIGS. 13(A) and 13(B) are enlarged views of an example cross-sectional configuration of a portion of FIG. 12(B). FIG. 14 is an enlarged view of an example perspective configuration of a portion of the heat-absorbing member of FIG. 12(A). FIG. 15 is a diagram showing an example of a manufacturing process for the heat-absorbing member of FIG. 12(A). FIG. 16 is a diagram showing a modified perspective configuration of the heat-absorbing member of FIG. 8. FIG. 17 is a diagram showing a modified perspective configuration of the heat-absorbing member of FIG. 8. Fig. 18 is a diagram illustrating a modified perspective configuration of the heat absorption member of Fig. 8. Fig. 19 is a diagram illustrating an example of a manufacturing process for the heat absorption member of Fig. 18. Fig. 20 is a diagram illustrating a modified perspective configuration of the heat absorption member of Fig. 8. Fig. 21 is a diagram illustrating an example of a manufacturing process for the heat absorption member of Fig. 20.

[0012] Hereinafter, embodiments of the present technology will be described in detail with reference to the drawings.

[0013] First, a battery pack according to an embodiment of the present technology will be described.

[0014] The battery pack described here is a power supply including multiple batteries, and is applicable to a variety of uses, such as electronic devices. The uses of the battery pack will be described in detail below. The type of battery is not particularly limited, and may be a primary battery or a secondary battery. The type of secondary battery is not particularly limited, and specifically, may be a lithium-ion secondary battery, which obtains battery capacity by utilizing the absorption and release of lithium ions. The number of batteries is not particularly limited, and may be set as desired. The following describes the case where the batteries are secondary batteries (lithium-ion secondary batteries). In other words, the battery pack described below is a power supply including multiple secondary batteries.

[0015] Fig. 1 illustrates an example of a perspective configuration of a battery pack 1 according to an embodiment of the present technology. Fig. 2 illustrates an example of a perspective configuration of a battery module 20 housed in the battery pack 1. Fig. 3 illustrates an example of an exploded perspective configuration of the battery pack 1. Fig. 4 illustrates an example of a cross-sectional configuration of the battery module 20.

[0016] 1 to 3, the battery pack 1 includes an outer case 10, a battery module 20, a plurality of metal tabs 60, and a control board 70. The control board 70 is connected to the positive and negative terminals of the battery module 20 via the plurality of metal tabs 60, for example, and has circuits that measure the voltage of the battery and the battery module 20, detect the remaining capacity of the battery module 20, and measure the current output from the battery module 20 to detect the presence or absence of an overcurrent.

[0017] The exterior case 10 houses the battery modules 20, the plurality of metal tabs 60, and the control board 70. For example, as shown in FIG. 3 , the exterior case 10 is composed of a lower case 10a and an upper case 10b. The lower case 10a and the upper case 10b are stacked together to form a housing space for housing the battery modules 20, the plurality of metal tabs 60, and the control board 70. The exterior case 10 (for example, the lower case 10a) is provided with external terminals 11 connected to the control board 70. The battery modules 20 are connected to the external terminals 11 via the control board 70.

[0018] The battery pack 1 has a discharge mode in which it supplies power output from the battery module 20 to a load via the external terminal 11. The battery pack 1 may also have a charge mode in which it stores power supplied via the external terminal 11 from a power source connected to the external terminal 11 in the battery module 20. When the battery 30 described below is a secondary battery, the control board 70 switches between the discharge mode and the charge mode depending on the type of connection object connected to the external terminal 11. When the battery 30 described below is a primary battery, the control board 70 operates only in the discharge mode.

[0019] The battery module 20 includes a plurality of batteries 30, as shown in FIGS. 2 and 3 , for example. The batteries 30 are electrically connected via a plurality of metal tabs 60. Each battery 30 includes a positive electrode 31 and a negative electrode 32, as shown in FIG. 2 , for example. Each battery 30 is a cylindrical battery in which the positive electrode 31 and the negative electrode 32 extend in directions facing each other. In the battery module 20, for example, some of the plurality of batteries 30 are connected in series with each other via a plurality of metal tabs 60. Furthermore, when the plurality of batteries 30 connected in series are referred to as a series unit, the series units are connected in parallel with each other via a plurality of metal tabs 60. Note that the connection of the plurality of batteries 30 is not limited to the above.

[0020] Each metal tab 60 is formed, for example, by a metal lead plate. Each battery 30 is a primary battery or a secondary battery. If each battery 30 is a secondary battery, the type of secondary battery is not particularly limited, but specifically, it may be a lithium-ion secondary battery that obtains battery capacity by utilizing the absorption and release of lithium ions. The following describes a case where each battery 30 is a secondary battery (lithium-ion secondary battery). In other words, the battery pack 1 described below is a power source including multiple secondary batteries.

[0021] 2 and 3, the battery module 20 further includes a battery holder 40 that supports the plurality of batteries 30, and a plurality of heat-absorbing members 50 arranged between the plurality of batteries 30. The battery holder 40 has a structure that supports the plurality of batteries 30 in a tiered manner with a predetermined gap between them. The heat-absorbing members 50 will be described in detail later.

[0022] Fig. 4 shows an example of the cross-sectional configuration of the battery module 20. The battery holder 40 is composed of a pair of holders 40a and 40b, as shown in Fig. 3 and Fig. 4. Both holders 40a and 40b have a common structure.

[0023] Each of the holders 40a and 40b has a side plate 41, as shown in Fig. 4 . The side plate 41 of the holder 40a and the side plate 41 of the holder 40b are arranged opposite each other with the plurality of batteries 30 between them in the extension direction of each battery 30 (the direction in which the positive electrodes 31 and negative electrodes 32 face each other). In the holders 40a and 40b, the side plate 41 has openings 42 at locations facing the positive electrodes 31 and negative electrodes 32 of each battery 30. Therefore, the positive electrodes 31 or negative electrodes 32 are exposed in the openings 42.

[0024] Each of the holders 40a, 40b further includes a support portion 43 that supports multiple batteries 30 in a tiered configuration with a predetermined gap between them, as shown in FIG. 4 . A side plate portion 41 is connected to each end of the support portion 43. Assume that the support portion 43 supports four or more cylindrical batteries 30 in a tiered configuration with a predetermined gap between them. In this case, the support portion 43 has an opening 44 at a location surrounded by four adjacent cylindrical batteries 30, as shown in FIG. 4 . A heat absorption module 50m, consisting of two overlapping heat absorption members 50, is positioned in a location surrounded by the four adjacent cylindrical batteries 30, as shown in FIGS. 4 and 5 , and contacts the outer peripheries of the four cylindrical batteries 30 through the opening 44.

[0025] The heat absorption module 50m extends in a direction parallel to the extension direction of each battery 30 (the direction in which the positive electrodes 31 and negative electrodes 32 face each other). Each heat absorption member 50 constituting the heat absorption module 50m also extends in a direction parallel to the extension direction of each battery 30 (the direction in which the positive electrodes 31 and negative electrodes 32 face each other). In the heat absorption module 50m, one heat absorption member 50 contacts the outer peripheral surfaces of two upper batteries 30 of the four adjacent cylindrical batteries 30, and the other heat absorption member 50 contacts the outer peripheral surfaces of two lower batteries 30 of the four adjacent cylindrical batteries 30. In the heat absorption module 50m, the flat surfaces (flat surface S4 (see FIG. 6B ) described below) of the two heat absorption members 50 overlap each other. The opening 44 contacts the side plate portion 41 of the holder 40a and the side plate portion 41 of the holder 40b, and the heat absorption member 50 contacts the side plate portion 41 of the holder 40a and the side plate portion 41 of the holder 40b through the opening 44.

[0026] Fig. 6(A) shows an example of a perspective configuration of the heat-absorbing member 50. Fig. 6(B) and Fig. 6(C) show an example of a cross-sectional configuration of the heat-absorbing member 50 taken along line A-A. Fig. 6(B) mainly lists reference numerals for the shape of the container 51, and Fig. 6(C) mainly lists reference numerals for the housing portion and flange portion of the container 51.

[0027] The heat absorption member 50 has a shape corresponding to the shape of the gaps between the multiple batteries 30 supported by the battery holder 40 (support portion 43). The heat absorption member 50 has an elongated columnar shape. Here, assume that four or more cylindrical batteries 30 are supported in layers by the battery holder 40 (support portion 43) with a predetermined gap between them. A heat absorption module 50m, consisting of two stacked heat absorption members 50, contacts the surfaces (outer peripheral surfaces) of four adjacent cylindrical batteries 30 and has a shape corresponding to the shape of the gaps between the four adjacent cylindrical batteries 30. The cross section of the heat absorption module 50m perpendicular to the extension direction of the heat absorption module 50m is generally rhombic. For example, as shown in FIG. 6B , the cross section of the heat absorption member 50 perpendicular to the extension direction of the heat absorption member 50 is generally triangular.

[0028] Here, the two adjacent cylindrical batteries 30 are referred to as the first battery 30 and the second battery 30. The heat-absorbing member 50 has an arc-shaped wall W1 (arc surface S1) extending along the outer circumferential surface of the first battery 30 and an arc-shaped wall W2 (arc surface S2) extending along the outer circumferential surface of the second battery 30. The arc-shaped wall W2 is positioned adjacent to the arc-shaped wall W1. The two arc-shaped walls W1, W2 (or the two arc-shaped surfaces S1, S2) have a concave shape conforming to the outer circumferential surfaces of the batteries 30. The heat-absorbing member 50 further has end walls W3 at both longitudinal ends of the heat-absorbing member 50 that constitute part of the longitudinal ends of the heat-absorbing member 50, and a flat wall W4 (flat surface S4) at a location facing the arc-shaped walls W1, W2 across a heat-absorbing agent 54 (described later). The end wall W3 is disposed adjacent to both the arcuate walls W1 and W2.

[0029] The heat absorbing member 50 includes, for example, a heat absorbing agent 54 and a container 51 that covers the heat absorbing agent 54, as shown in FIGS. 6B and 6C.

[0030] The container 51 covers the heat-absorbing agent 54. The container 51 is formed, for example, by filling a container formed by heat-sealing two laminates 52 and 53 except for one side with the heat-absorbing agent 54, and then heat-sealing the filling port on the remaining side after filling. Thus, the container 51 contains the heat-absorbing agent 54. The laminate 52 corresponds to a specific example of a "first container part" according to an embodiment of the present technology. The laminate 53 corresponds to a specific example of a "second container part" according to an embodiment of the present technology.

[0031] 6(A) and 6(C), the container 51 has a storage section 51A that stores the heat-absorbing agent 54, and a flange section 51B formed around the storage section 51A. The storage section 51A corresponds to a substantially triangular prism-shaped portion of the container 51 that is formed by the arc walls W1 and W2, the end wall W3, and a portion of the flat wall W4. The flange section 51B corresponds to a plate-shaped portion of the container 51 that is formed to surround the storage section 51A when viewed from the normal direction of the flat wall W4.

[0032] The laminate 52 has a first housing portion 52A that constitutes a portion of the housing portion 51A and a first flange portion 52B that constitutes a portion of the flange portion 51B. The first housing portion 52A corresponds to the portion formed by the arc walls W1, W2 and the end wall W3. The first housing portion 52A and the first flange portion 52B are integrally formed with each other, and the laminate 52 is connected to a second flange portion 53B (described below) at the first flange portion 52B. The laminate 53 has a second housing portion 53A that constitutes a portion of the housing portion 51A and a second flange portion 53B that constitutes a portion of the flange portion 51B. The second housing portion 53A corresponds to the portion formed by a portion of the flat wall W4. The second housing portion 53A and the second flange portion 53B are integrally formed with each other, and the laminate 53 is connected to the first flange portion 52B at the second flange portion 53B.

[0033] The first accommodating portion 52A corresponds to a specific example of a "first accommodating portion" according to an embodiment of the present technology. The first flange portion 52B corresponds to a specific example of a "first flange portion" according to an embodiment of the present technology. The second accommodating portion 53A corresponds to a specific example of a "second accommodating portion" according to an embodiment of the present technology. The second flange portion 53B corresponds to a specific example of a "second flange portion" according to an embodiment of the present technology.

[0034] 7(A) and 7(B) are enlarged cross-sectional views of an example of a portion of FIG. 6(B). FIG. 7(A) shows an enlarged view of the boundary between the arcuate wall W1 and the arcuate wall W2. FIG. 7(B) shows an enlarged view of the portion where the laminate 52 and the laminate 53 are connected to each other. The laminate 52, the first housing portion 52A, and the first flange portion 52B are configured to include a resin layer 52a, as shown in FIGS. 7(A) and 7(B). The laminate 53, the second housing portion 53A, and the second flange portion 53B are configured to include a resin layer 53a, as shown in FIGS. 7(A) and 7(B). The resin layers 52a and 53a are configured from a resin material such as polyethylene, polystyrene, polypropylene, or polycarbonate.

[0035] The laminate 52, the first housing portion 52A, and the first flange portion 52B may be formed of, for example, a laminate film. For example, as shown in Figures 7(A) and 7(B), the laminate 52, the first housing portion 52A, and the first flange portion 52B are formed by including a resin layer 52a and a metal layer 52b in this order from the heat-absorbing agent 54 side. In this case, the laminate 52, the first housing portion 52A, and the first flange portion 52B are formed by including the resin layer 52a. The metal layer 52b is formed of, for example, a metal foil such as aluminum foil.

[0036] The laminate 53, the second housing portion 53A, and the second flange portion 53B may be formed of, for example, a laminate film. For example, as shown in Figures 7(A) and 7(B), the laminate 53, the second housing portion 53A, and the second flange portion 53B are formed by including a resin layer 53a and a metal layer 53b in this order from the heat-absorbing agent 54 side. In this case, the laminate 53, the second housing portion 53A, and the second flange portion 53B are formed by including the resin layer 53a. The metal layer 53b is formed of, for example, a metal foil such as aluminum foil.

[0037] The heat-absorbing agent 54 is made of, for example, a liquid containing water or a hydrogel. When using a hydrogel as the heat-absorbing agent 161, it is preferable to use a synthetic polymer gel. Examples of materials for the synthetic polymer gel include sodium polyacrylate (PNaAA), polyvinyl alcohol (PVA), polyhydroxyethyl methacrylate (PHE-MA), and silicone hydrogel.

[0038] As shown in FIG. 7A, the laminate 52 has a shape bent at an acute angle at the boundary BD between the arcuate wall W1 and the arcuate wall W2. In the flange portion 51B, as shown in FIG. 7B, the laminate 52 and the laminate 53 are welded to each other, with a portion of the resin layer 52a of the laminate 52 and a portion of the resin layer 53a of the laminate 53 welded to each other. The portion where a portion of the resin layer 52a of the laminate 52 and a portion of the resin layer 53a of the laminate 53 are welded to each other is designated as a welded portion 52D in FIG. 7B. In the flange portion 51B, as shown in FIG. 7B, the first flange portion 52B and the second flange portion 53B are welded to each other, with a portion of the resin layer 52a of the first flange portion 52B and a portion of the resin layer 53a of the second flange portion 53B welded to each other. In FIG. 7B, the portion where a part of the resin layer 52a of the first flange portion 52B and a part of the resin layer 53a of the second flange portion 53B are welded to each other is a welded portion 52D.

[0039] In the flange portion 51B, the welded portion 52D penetrates in the in-plane direction of the stacking of the flange portion 51B, as shown in FIG. 7B . Therefore, when the welded portion 52D in the flange portion 51B is heated, for example, by the heat of a battery 30 that is abnormally generating heat, the welded portion 52D peels off due to the heat, thereby connecting the storage space of the storage portion 51A to the outside. As a result, the heat-absorbing agent 54 leaks out through the end of the flange portion 51B to the outside (for example, the periphery of the battery 30 that is abnormally generating heat). Therefore, the welded portion 52D functions as a peelable portion that can peel off due to heat, thereby connecting the storage space of the storage portion 51A to the outside.

[0040] The welded portion 52D does not have to be exposed at the end surface of the flange portion 51B. However, in this case, the resin layer 52a of the laminate 52 and the resin layer 53a of the laminate 53 may simply be in physical contact between the end surface of the flange portion 51B and the welded portion 52D, and may be peelable without heating. For example, the resin layer 52a of the laminate 52 and the resin layer 53a of the laminate 53 may be in contact with each other via an adhesive between the end surface of the flange portion 51B and the welded portion 52D. Furthermore, the welded portion 52D does not have to be exposed to the storage space of the storage portion 51A. However, in this case, the resin layer 52a of the laminate 52 and the resin layer 53a of the laminate 53 may simply be in physical contact between the welded portion 52D and the storage space of the storage portion 51A, and may be peelable without heating. For example, the resin layer 52a of the laminate 52 and the resin layer 53a of the laminate 53 may be in contact with each other via an adhesive between the welded portion 52D and the storage space of the storage portion 51A. Even in this case, when the welded portion 52D in the flange portion 51B is heated, for example, by the heat of a battery 30 that is abnormally generating heat, the welded portion 52D peels off due to the heat, thereby connecting the storage space of the storage portion 51A to the outside. As a result, the heat-absorbing agent 54 leaks out through the end of the flange portion 51B to the outside (e.g., the periphery of the battery 30 that is abnormally generating heat). Therefore, the welded portion 52D functions as a peelable portion that can peel off due to heat, thereby connecting the storage space of the storage portion 51A to the outside.

[0041] FIG. 8 is an enlarged perspective view of a portion of the heat-absorbing member 50 in FIG. 6A. FIG. 9 is an enlarged cross-sectional view of a portion of the battery module 20 in FIG. 2. FIG. 9 shows an example cross-sectional view including a cutout 51C, which will be described later. In this embodiment, the container 51 has one or more cutouts 51C, as shown in FIGS. 6A and 8. Each cutout 51C is provided in the flange 51B. The bonded portion (welded portion 52D) of the first flange 52B and the second flange 53B has a portion (narrowed region R1) where the width Da of the bonded portion (welded portion 52D) is locally narrower than the width Db of the flange 51B. The width Db of the flange portion 51B refers to the width of the plate-like portion of the laminate 52, 53, more specifically, the width of the plate-like portion on the side where the narrow region R1 is present in the laminate 52, 53. Note that Fig. 8 illustrates an example in which the maximum value of the width Da of the welded portion 52D is equal to the width Db of the flange portion 51B.

[0042] Each cutout 51C is formed to penetrate the laminate 52, 53. Each cutout 51C is formed to penetrate the adhesive portion (welded portion 52D) between the resin layer 52a of the first flange 52B and the resin layer 53a of the second flange 53B. Each cutout 51C is provided adjacent to the welded portion 52D. For example, as shown in FIG. 8 , each cutout 51C may have an acute corner that protrudes toward the storage space α of the storage portion 51A when viewed from a direction in which the entire flange 51B can be seen. In this case, a narrow region R1 may be formed adjacent to this acute corner.

[0043] 9, each notch 51C is disposed adjacent to two adjacent batteries 30. As shown in FIG. 6A, each notch 51C is disposed in a central region of the heat absorption member 50 in the longitudinal direction of the heat absorption member 50. Here, the "central region" refers to, for example, a region of the flange portion 51B that is separated from the end wall W3 by a length equal to or greater than the height of the end wall W3.

[0044] Next, an example of a manufacturing method for the heat-absorbing member 50 will be described. FIG. 10 illustrates an example of the manufacturing process for the heat-absorbing member 50. First, a stack 52' formed into a mountain shape by drawing is overlapped with a flat stack 53'. Next, mold pieces Ma and Mb are pressed against the flange portion of the stack 52', while the stack 53' is supported by a flat mold piece Mc. The mold pieces Ma and Mb are then heated to a predetermined temperature ( FIG. 10 ). As a result, the heat from the mold pieces Ma and Mb is transferred to the resin layers 52a and 53a within the stacks 52' and 53', respectively, welding portions of the resin layers 52a and 53a to form a welded portion 52D. At this time, one side is not fused, and the remaining side is fused. As a result, the stacks 52' and 53' become container-shaped. Then, the mold pieces Ma, Mb, and Mc are detached from the stacks 52' and 53'. Next, the laminates 52' and 53' are heat-sealed on all but one side of the container, and the heat-absorbing agent 54 is filled into the container. After filling, the filling port on the remaining side is heat-sealed. One or more notches 51C are then formed in predetermined locations on the laminates 52' and 53'. In this manner, the heat-absorbing member 50 is manufactured.

[0045] Next, the effects of the battery pack 1 will be described.

[0046] As electronic devices have become widespread, development of batteries as power sources for these devices has progressed. In this case, battery packs containing multiple batteries have been proposed to facilitate easy and safe handling of the batteries.

[0047] Various studies have been conducted on technologies related to the configuration of a battery pack. Specifically, a heat-absorbing member is in contact with the side surface of a battery unit, and the heat-absorbing member contains a heat-absorbing agent (gel-like fluid) inside an exterior film (see, for example, Patent Document 1).

[0048] However, in a battery pack, depending on the arrangement and structure of the heat absorbing member, it may be difficult for the heat absorbing member to sufficiently cool an abnormally heated battery.

[0049] On the other hand, in this embodiment, a notch 51C is provided in the container 51 of the heat-absorbing member 50 arranged adjacent to the battery 30. This allows the heat-absorbing agent 54 leaking to the outside through the notch 51C to come into contact with the abnormally heated battery 30 and cool the abnormally heated battery 30. Thus, by providing the notch 51C in a desired location on the container 51, the abnormally heated battery 30 can be effectively cooled. Therefore, the abnormally heated battery 30 can be sufficiently cooled by the heat-absorbing member 50.

[0050] In this embodiment, the width Da of the bonded portion (welded portion 52D) between the first flange portion 52B and the second flange portion 53B is locally narrower than the width Db of the flange portion 51B. The width Da of the welded portion 52D is locally narrowed by the cutout portion 51C. When the welded portion 52D in the flange portion 51B is heated by the heat of the abnormally heated battery 30, the narrowed region R1 of the welded portion 52D created by the cutout portion 51C peels off first, connecting the storage space of the storage portion 51A to the outside. As a result, the heat-absorbing agent 54 leaks out through the end of the flange portion 51B to the outside (e.g., the periphery of the abnormally heated battery 30). The leaked heat-absorbing agent 54 comes into contact with the abnormally heated battery 30 and can cool the abnormally heated battery 30. Therefore, by providing the cutout portion 51C at a desired location on the container 51, it is possible to effectively cool the abnormally heated battery 30. From the above, it is possible to sufficiently cool the abnormally heated battery 30 with the heat absorption member 50.

[0051] In this embodiment, the first and second housing sections 52A and 53A are shaped so that the housing section 51A has a generally triangular prism shape. This allows the heat absorption module 50m, consisting of two stacked heat absorption members 50, to contact the outer peripheries of the four adjacent cylindrical batteries 30 when the module is positioned so that it is surrounded by four adjacent cylindrical batteries 30. As a result, the leaked heat absorption agent 54 contacts the abnormally heated battery 30 and cools it. Therefore, by providing the cutouts 51C at desired locations on the container 51, the abnormally heated battery 30 can be effectively cooled. As a result, the heat absorption members 50 can sufficiently cool the abnormally heated battery 30.

[0052] In this embodiment, the portion of the stack 52 corresponding to the first flange 52B and the portion of the stack 53 corresponding to the second flange 53B are bonded to each other. The cutout 51C penetrates the stacks 52 and 53. When the welded portion 52D is heated by the heat of the abnormally heated battery 30, the narrowed region R1 of the welded portion 52D, created by the cutout 51C, peels off first, connecting the storage space of the storage portion 51A to the outside. As a result, the heat-absorbing agent 54 leaks out through the end of the flange 51B to the outside (e.g., the periphery of the abnormally heated battery 30). The leaked heat-absorbing agent 54 comes into contact with the abnormally heated battery 30 and can cool the abnormally heated battery 30. Therefore, by providing the cutout 51C at a desired location on the container 51, the abnormally heated battery 30 can be effectively cooled. As a result of the above, the heat-absorbing member 50 can sufficiently cool the abnormally heated battery 30 .

[0053] In this embodiment, the resin layer 52a of the first flange portion 52B and the resin layer 53a of the second flange portion 53B are welded to each other, and the cutout portion 51C is formed to penetrate the welded portion 52D between the resin layer 52a of the first flange portion 52B and the resin layer 53a of the second flange portion 53B. As a result, when the welded portion 52D is heated by the heat of the abnormally heated battery 30, the narrowed region R1 of the welded portion 52D created by the cutout portion 51C peels off first, connecting the storage space of the storage portion 51A to the outside. As a result, the heat-absorbing agent 54 leaks out through the end of the flange portion 51B to the outside (e.g., the periphery of the abnormally heated battery 30), and the leaked heat-absorbing agent 54 comes into contact with the abnormally heated battery 30 and can cool the abnormally heated battery 30. Therefore, by providing the cutout portion 51C at a desired location on the container 51, it is possible to effectively cool the abnormally heated battery 30. From the above, it is possible to sufficiently cool the abnormally heated battery 30 with the heat absorption member 50.

[0054] In this embodiment, the cutouts 51C are positioned adjacent to two adjacent batteries 30. The cutouts 51C are located in the longitudinal center region of the heat-absorbing member 50. When the welded portion 52D is heated by the heat of the abnormally heated battery 30, the narrowed region R1 of the welded portion 52D created by the cutouts 51C peels off first, connecting the storage space of the storage portion 51A to the outside. As a result, the heat-absorbing agent 54 leaks out through the end of the flange portion 51B to the outside (e.g., the periphery of the abnormally heated battery 30). The leaked heat-absorbing agent 54 comes into contact with the abnormally heated battery 30 and can cool it. Therefore, by providing the cutouts 51C in desired locations on the container 51, the abnormally heated battery 30 can be effectively cooled. As a result, the heat-absorbing member 50 can sufficiently cool the abnormally heated battery 30.

[0055] Next, a modification of the battery pack 1 according to the above embodiment will be described.

[0056] (Variation A) FIG. 11A shows a variation of the cross-sectional configuration of the heat-absorbing member shown in FIG. 7A. FIG. 11B shows a variation of the cross-sectional configuration of the heat-absorbing member shown in FIG. 7B. In the above embodiment, the laminate 52 may have a configuration in which a metal layer 52b is sandwiched between resin layers 52a and 52c, as shown in FIGS. 11A and 11B. Furthermore, in the above embodiment, the laminate 53 may have a configuration in which a metal layer 53b is sandwiched between resin layers 53a and 53c, as shown in FIG. 11B. The resin layers 52c and 53c are made of a resin material such as polyethylene, polystyrene, polypropylene, or polycarbonate. In this case, the cutout portion 51C penetrates the resin layers 52c and 53c. In this case, the metal layer 52b is coated with the resin layer 52c, and the metal layer 53b is coated with the resin layer 53c, so that it is possible to more reliably prevent the metal layers 52b, 53b from shorting out with the conductors within the battery module 20.

[0057] (Variation B) Fig. 12(A) shows a variation of the perspective configuration of the heat absorbing member of Fig. 6(A). Figs. 12(B) and 12(C) show an example of the cross-sectional configuration of the heat absorbing member of Fig. 12(A) taken along line A-A. Fig. 12(B) mainly lists reference numerals for the shape of the container 51, while Fig. 12(C) mainly lists reference numerals for the housing portion and flange portion of the container 51.

[0058] In this modified example, the heat absorption member 50 has a shape corresponding to the shape of the gaps between the multiple batteries 30 supported by the battery holder 40 (support portion 43). The heat absorption member 50 has a long, thin columnar shape, similar to the batteries 30. Assume that four or more cylindrical batteries 30 are supported in layers by the battery holder 40 (support portion 43) with a predetermined gap between them. The heat absorption member 50 contacts the surfaces (outer peripheral surfaces) of four adjacent cylindrical batteries 30, and has a shape corresponding to the shape of the gaps between the four adjacent cylindrical batteries 30. The cross section of the heat absorption member 50 perpendicular to the extension direction is generally diamond-shaped. For example, as shown in FIG. 12B , the cross section of the heat absorption member 50 perpendicular to the extension direction is generally diamond-shaped.

[0059] Here, the two adjacent cylindrical batteries 30 are referred to as the first battery 30 and the second battery 30. In this case, the heat absorption member 50 has an arc wall W1 (arc surface S1) extending along the outer circumferential surface of the first battery 30 and an arc wall W2 (arc surface S2) extending along the outer circumferential surface of the second battery 30. The arc wall W2 is disposed adjacent to the arc wall W1. The two arc walls W1, W2 (or the two arc surfaces S1, S2) have a concave shape that conforms to the outer circumferential surfaces of the batteries 30.

[0060] Furthermore, the two adjacent cylindrical batteries 30 are referred to as the third battery 30 and the fourth battery 30. In this case, the heat absorption member 50 has an arc wall W5 (arc surface S5) extending along the outer circumferential surface of the third battery 30 and an arc wall W6 (arc surface S6) extending along the outer circumferential surface of the fourth battery 30. The arc wall W6 is located adjacent to the arc wall W5. The two arc walls W5, W6 (or the two arc surfaces S5, S6) have a concave shape that follows the outer circumferential surfaces of the batteries 30.

[0061] The heat absorption member 50 further has end walls W3 at both longitudinal ends of the heat absorption member 50, which constitute part of the longitudinal ends of the heat absorption member 50. The end walls W3 are disposed adjacent to both the arc walls W1 and W2. The end walls W3 are also disposed adjacent to both the arc walls W5 and W6.

[0062] The heat absorbing member 50 includes, for example, a heat absorbing agent 54 and a container 51 that covers the heat absorbing agent 54, as shown in FIGS. 12B and 12C.

[0063] The container 51 covers the heat-absorbing agent 54. The container 51 is formed, for example, by heating and molding the heat-absorbing agent 54 and the laminates 52 and 55 in a state where the heat-absorbing agent 54 is covered with the laminates 52 and 55. Thus, the container 51 contains the heat-absorbing agent 54.

[0064] 12(A) and 12(C), the container 51 has a storage section 51A that stores the heat-absorbing agent 54, and a flange section 51B formed around the storage section 51A. The storage section 51A corresponds to a generally diamond-shaped columnar section of the container 51 that is formed by the arc-shaped walls W1 and W2, the end wall W3, and the arc-shaped walls W5 and W6. The flange section 51B corresponds to a plate-shaped section of the container 51 that is formed to surround the storage section 51A when viewed from a direction that allows the entire arc-shaped walls W1 and W2 to be seen.

[0065] The laminate 52 has a first housing portion 52A that constitutes a portion of the housing portion 51A and a first flange portion 52B that constitutes a portion of the flange portion 51B. The first housing portion 52A corresponds to the portion formed by the arc walls W1, W2 and the end wall W3. The first housing portion 52A and the first flange portion 52B are integrally formed with each other, and the laminate 52 is connected to a second flange portion 53B (described below) at the flange portion 51B. The laminate 55 has a third housing portion 55A that constitutes a portion of the housing portion 51A and a third flange portion 55B that constitutes a portion of the flange portion 51B. The third housing portion 55A corresponds to the portion formed by the arc walls W5, W6 and the end wall W3. The third housing portion 55A and the third flange portion 55B are integrally formed with each other, and the laminate 55 is connected to the first flange portion 52B at the flange portion 51B.

[0066] 13(A) and 13(B) are enlarged cross-sectional views of an example of a portion of FIG. 12(B). FIG. 13(A) shows an enlarged view of the boundary BD between the arcuate wall W5 and the arcuate wall W6. FIG. 13(B) shows an enlarged view of the portion where the stack 52 and the stack 55 are connected to each other. The stack 55, the third housing portion 55A, and the third flange portion 55B are configured to include a resin layer 55a, as shown in FIGS. 13(A) and 13(B), for example. The stack 55, the third housing portion 55A, and the third flange portion 55B are configured to include a resin layer 55a, as shown in FIGS. 13(A) and 13(B), for example. The resin layer 55a is configured from a resin material such as polyethylene, polystyrene, polypropylene, or polycarbonate.

[0067] The laminate 55, the third housing portion 55A, and the third flange portion 55B may be formed of, for example, a laminate film. For example, as shown in Figures 13(A) and 13(B), the laminate 55, the third housing portion 55A, and the third flange portion 55B are formed by including a resin layer 55a and a metal layer 55b in this order from the heat-absorbing agent 54 side. In this case, the laminate 55, the third housing portion 55A, and the third flange portion 55B are formed by including the resin layer 55a. The metal layer 55b is formed of, for example, a metal foil such as aluminum foil.

[0068] As shown in FIG. 13A, the laminate 55 has a shape bent at an acute angle at the boundary BD between the arcuate walls W5 and W6. At the boundary BD (bent portion) between the arcuate walls W5 and W6, a portion of the resin layer 52a of the arcuate wall W5 and a portion of the resin layer 52a of the arcuate wall W6 are welded to each other, as shown in FIG. 13A. The portion where the portion of the resin layer 52a of the arcuate wall W5 and a portion of the resin layer 52a of the arcuate wall W6 are welded to each other is a welded portion 52D in FIG. 13A. At the flange portion 51B, as shown in FIG. 13B, the laminate 52 and the laminate 55 are welded to each other, and a portion of the resin layer 52a of the laminate 52 and a portion of the resin layer 55a of the laminate 55 are welded to each other. In Fig. 13(B), a portion where a part of the resin layer 52a of the laminate 52 and a part of the resin layer 53a of the laminate 55 are welded to each other is designated as welded portion 52D. In the flange portion 51B, for example, as shown in Fig. 13(B), the first flange portion 52B and the third flange portion 55B are welded to each other, and a part of the resin layer 52a of the first flange portion 52B and a part of the resin layer 55a of the third flange portion 55B are welded to each other. In Fig. 13(B), a portion where a part of the resin layer 52a of the first flange portion 52B and a part of the resin layer 55a of the third flange portion 55B are welded to each other is designated as welded portion 52D.

[0069] As shown in FIG. 13B, the welded portion 52D is exposed on the end surface of the flange portion 51B. Furthermore, the welded portion 52D exposes the storage space of the storage portion 51A. That is, the welded portion 52D penetrates the flange portion 51B in the in-plane direction of the stacking of the flange portion 51B. Therefore, when the welded portion 52D in the flange portion 51B is heated, for example, by the heat of a battery 30 that is abnormally generating heat, the welded portion 52D peels off due to the heat, thereby connecting the storage space of the storage portion 51A to the outside. As a result, the heat-absorbing agent 54 leaks out through the end of the flange portion 51B to the outside (e.g., the periphery of the battery 30 that is abnormally generating heat). Therefore, the welded portion 52D functions as a peelable portion that can peel off due to heat, thereby connecting the storage space of the storage portion 51A to the outside.

[0070] The welded portion 52D does not have to be exposed at the end surface of the flange portion 51B. However, in this case, the resin layer 52a of the laminate 52 and the resin layer 55a of the laminate 55 may be in physical contact between the end surface of the flange portion 51B and the welded portion 52D, and may be peelable without heating. The welded portion 52D does not have to be exposed to the storage space of the storage portion 51A. However, in this case, the resin layer 52a of the laminate 52 and the resin layer 55a of the laminate 55 may be in physical contact between the welded portion 52D and the storage space of the storage portion 51A, and may be peelable without heating. Even in this case, when the welded portion 52D in the flange portion 51B is heated, for example, by the heat of a battery 30 that is abnormally generating heat, the welded portion 52D peels off due to the heat, thereby connecting the storage space of the storage portion 51A to the outside. As a result, the heat-absorbing agent 54 leaks out through the end of the flange portion 51B to the outside (for example, to the periphery of the abnormally heated battery 30). Therefore, the welded portion 52D functions as a peelable portion that can be peeled off by heating to connect the storage space of the storage portion 51A to the outside.

[0071] FIG. 14 is an enlarged perspective view of a portion of the heat-absorbing member 50 shown in FIG. 12A. In this modification, the container 51 is provided with one or more cutouts 51C, as shown in FIGS. 12A and 14. Each cutout 51C is provided in the flange 51B. The welded portion 52D has a narrowed region R1 where the width Da of the welded portion 52D is locally narrower than the width Db of the flange 51B. The width Db of the flange 51B refers to the width of the plate-shaped portion of the laminate 52, 55, more specifically, the width of the plate-shaped portion of the laminate 52, 55 on the side where the narrowed region R1 exists. FIG. 14 illustrates an example in which the maximum width Da of the welded portion 52D is equal to the width Db of the flange 51B.

[0072] Each cutout 51C is formed to penetrate the laminate 52, 55. Each cutout 51C is formed to penetrate the welded portion 52D. Each cutout 51C is provided adjacent to the welded portion 52D. For example, as shown in FIG. 14 , each cutout 51C may have an acute corner that protrudes toward the housing space α of the housing portion 51A when viewed from a direction in which the entire flange portion 51B can be seen. In this case, a narrow region R1 may be formed adjacent to this acute corner.

[0073] Each cutout 51C is located adjacent to two adjacent batteries 30. For example, as shown in Fig. 12A, each cutout 51C is located in the central region of the heat absorption member 50 in the longitudinal direction of the heat absorption member 50. Here, the "central region" refers to, for example, a region of the flange portion 51B that is separated from the end wall W3 by a length equal to or greater than the height of the end wall W3.

[0074] Next, an example of a manufacturing method for the heat-absorbing member 50 according to this modified example will be described. FIG. 15 illustrates an example of the manufacturing process for the heat-absorbing member 50. First, stacked bodies 52' and 55' formed into a mountain shape by drawing are stacked together. Next, mold pieces Ma and Mb are pressed against the flange portion of stacked body 52', and mold pieces Md and Me are pressed against the flange portion of stacked body 55', and each mold piece Ma, Mb, Md, and Me is heated to a predetermined temperature ( FIG. 15 ). As a result, the heat from each mold piece Ma, Mb, Md, and Me is transferred to the resin layers 52a and 55a within stacked bodies 52' and 55', respectively, and portions of the resin layers 52a and 55a are welded to form welded portion 55D. At this time, one side is not fused, and the remaining side is fused. As a result, stacked bodies 52' and 55' become container-shaped. Thereafter, the mold pieces Ma, Mb, Md, and Me are removed from the laminates 52', 55'. Next, the laminates 52', 55' are heat-sealed on all but one side of the container, and the heat-absorbing agent 54 is filled into the container. After filling, the filling port on the remaining side is heat-sealed. Then, one or more notches 51C are formed in predetermined locations of the laminates 52', 55'. In this manner, the heat-absorbing member 50 is manufactured.

[0075] In this modification, a notch 51C is provided in the container 51 of the heat absorption member 50 arranged adjacent to the battery 30. This allows the heat absorption agent 54 leaking to the outside through the notch 51C to come into contact with the abnormally heated battery 30 and cool the abnormally heated battery 30. By providing the notch 51C in a desired location on the container 51, the abnormally heated battery 30 can be effectively cooled. Therefore, the abnormally heated battery 30 can be sufficiently cooled by the heat absorption member 50.

[0076] In this modification, the width Da of the welded portion 52D of the first flange portion 52B and the third flange portion 55B is locally narrower than the width Db of the flange portion 51B. The width Da of the welded portion 52D is locally narrowed by the cutout portion 51C. When the welded portion 52D of the flange portion 51B is heated by the heat of the abnormally heated battery 30, the narrowed region R1 of the welded portion 52D created by the cutout portion 51C peels off first, connecting the storage space of the storage portion 51A to the outside. As a result, the heat-absorbing agent 54 leaks out through the end of the flange portion 51B (e.g., to the periphery of the abnormally heated battery 30), and the leaked heat-absorbing agent 54 comes into contact with the abnormally heated battery 30, thereby cooling the abnormally heated battery 30. Therefore, by providing the cutout portion 51C at a desired location on the container 51, it is possible to effectively cool the abnormally heated battery 30. From the above, it is possible to sufficiently cool the abnormally heated battery 30 with the heat absorption member 50.

[0077] In this modification, the first and third storage sections 52A and 55A are shaped so that the exterior of the storage section 51A is a generally diamond-shaped column. This allows the heat-absorbing member 50 to contact the outer peripheries of the four adjacent cylindrical batteries 30 when the heat-absorbing member 50 is positioned so that it is surrounded by four adjacent cylindrical batteries 30. As a result, the leaked heat-absorbing agent 54 comes into contact with the abnormally heated battery 30, thereby cooling the abnormally heated battery 30. Therefore, by providing the cutouts 51C at desired locations on the container 51, the abnormally heated battery 30 can be effectively cooled. As a result, the heat-absorbing member 50 can sufficiently cool the abnormally heated battery 30.

[0078] In this modification, the portion of the stack 52 corresponding to the first flange 52B and the portion of the stack 55 corresponding to the third flange 55B are bonded to each other. The cutout 51C penetrates the stacks 52 and 55. When the welded portion 52D is heated by the heat of the abnormally heated battery 30, the narrowed region R1 of the welded portion 52D created by the cutout 51C peels off first, connecting the storage space of the storage portion 51A to the outside. As a result, the heat-absorbing agent 54 leaks out through the end of the flange 51B to the outside (e.g., the periphery of the abnormally heated battery 30). The leaked heat-absorbing agent 54 comes into contact with the abnormally heated battery 30 and can cool the abnormally heated battery 30. Therefore, by providing the cutout 51C at a desired location on the container 51, the abnormally heated battery 30 can be effectively cooled. As a result of the above, the heat-absorbing member 50 can sufficiently cool the abnormally heated battery 30 .

[0079] In this modification, the resin layer 52a of the first flange portion 52B and the resin layer 55a of the third flange portion 55B are welded to each other, and the cutout portion 51C is formed to penetrate the welded portion 52D between the resin layer 52a of the first flange portion 52B and the resin layer 55a of the third flange portion 55B. As a result, when the welded portion 52D is heated by the heat of the abnormally heated battery 30, the narrowed region R1 of the welded portion 52D created by the cutout portion 51C peels off first, connecting the storage space of the storage portion 51A to the outside. As a result, the heat-absorbing agent 54 leaks out through the end of the flange portion 51B to the outside (e.g., the periphery of the abnormally heated battery 30), and the leaked heat-absorbing agent 54 comes into contact with the abnormally heated battery 30 and can cool the abnormally heated battery 30. Therefore, by providing the cutout portion 51C at a desired location on the container 51, it is possible to effectively cool the abnormally heated battery 30. From the above, it is possible to sufficiently cool the abnormally heated battery 30 with the heat absorption member 50.

[0080] In this modification, the cutouts 51C are positioned adjacent to two adjacent batteries 30. The cutouts 51C are located in the longitudinal center region of the heat-absorbing member 50. As a result, when the welded portion 52D is heated by the heat of the abnormally heated battery 30, the narrowed region R1 of the welded portion 52D created by the cutouts 51C peels off first, connecting the storage space of the storage portion 51A to the outside. As a result, the heat-absorbing agent 54 leaks out through the end of the flange portion 51B to the outside (e.g., the periphery of the abnormally heated battery 30). The leaked heat-absorbing agent 54 comes into contact with the abnormally heated battery 30 and can cool it. Therefore, by providing the cutouts 51C in desired locations on the container 51, the abnormally heated battery 30 can be effectively cooled. As a result, the abnormally heated battery 30 can be sufficiently cooled by the heat-absorbing member 50.

[0081] (Variation C) In the above embodiment and its variations, for example, as shown in FIG. 16 , a through hole 51D may be provided instead of the cutout 51C. The through hole 51D is formed to penetrate the flange 51B, the welded portion 52D, and the laminates 52 and 53. When viewed from the normal direction of the flange 51B, the through hole 51D has a circular or elliptical shape. Two narrow regions R2 and R3 are provided adjacent to the through hole 51D in the welded portion 52D. If the width of the narrow region R2 is Da1 and the width of the narrow region R3 is Da2, Da1 + Da2 corresponds to the width Da in the above embodiment and its variations. The width Da (= Da1 + Da2) of the welded portion 52D at the location of the narrow regions R2 and R3 is narrower than the width Db of the flange 51B. Even in this case, the same effect as when the cutout 51C is provided can be obtained.

[0082] In this modification, the through hole 51D may be rectangular when viewed from the normal direction of the flange portion 51B, as shown in Fig. 17 . In this case, the longitudinal direction of the through hole 51D is parallel to the extension direction of the end side of the flange portion 51B, for example. The longitudinal direction of the through hole 51D may be perpendicular to the extension direction of the end side of the flange portion 51B. Even in this case, the same effect as when the notch portion 51C is provided can be obtained.

[0083] (Variation D) In ​​the above embodiment and its variations, for example, as shown in FIG. 18 , a non-welded region 51E may be provided instead of the cutout portion 51C. The non-welded region 51E is a region where the laminate 52 (resin layer 52a) and the laminate 53 (resin layer 53a) are simply in contact with each other, allowing the laminate 52 (resin layer 52a) and the laminate 53 (resin layer 53a) to be peeled apart without heating. The non-welded region 51E is exposed, for example, at the end of the flange portion 51B. A gap may exist in the non-welded region 51E, or the laminate 52 (resin layer 52a) and the laminate 53 (resin layer 53a) may be in close contact with each other, eliminating the need for a gap. The non-welded region 51E may have, for example, an acute corner that protrudes toward the storage space α of the storage portion 51A when viewed from a direction that allows the entire flange portion 51B to be seen. In this case, a narrow region R4 may be formed adjacent to this acute corner, and even in this case, the same effect as when the notch 51C is provided can be obtained.

[0084] Next, a method for manufacturing the non-welded region 51E will be described. For example, as shown in FIG. 19, the laminates 52 and 53 are placed on a mold piece Mg having a flat surface. Next, the end of the laminate 52 is pressed with a mold piece Mf having a cutout portion Mf1 corresponding to the shape of the non-welded region 51E. This forms a welded portion 52D having a narrow region R4. As a result, the area where the welded portion 52D is not formed becomes the non-welded region 51E.

[0085] (Variation E) In the above embodiment and variations thereof, for example, as shown in FIG. 20 , a non-welded region 51F may be provided instead of the cutout portion 51C. The non-welded region 51F is a region where the laminate 52 (resin layer 52a) and the laminate 53 (resin layer 53a) are simply in contact with each other, allowing the laminate 52 (resin layer 52a) and the laminate 53 (resin layer 53a) to be separated without heating. The non-welded region 51F is provided, for example, in a portion of the flange portion 51B that communicates with the storage space α of the storage portion 51A. A void may be present in the non-welded region 51F, or the laminate 52 (resin layer 52a) and the laminate 53 (resin layer 53a) may be in close contact with each other, eliminating the void. If a void is present in the non-welded region 51F, the void may be filled with a heat-absorbing agent 54. For example, when viewed from a direction in which the entire flange portion 51B can be seen, the non-welded region 51F may have an acute corner that protrudes toward the end face of the flange portion 51B. In this case, a narrow region R5 may be formed adjacent to the acute corner. Even in this case, the same effect as when the notch 51C is provided can be obtained.

[0086] Next, a method for manufacturing the non-welded region 51F will be described. For example, as shown in FIG. 21 , the laminates 52 and 53 are placed on a mold piece Mi having a flat surface. Next, the end of the laminate 52 is pressed with a mold piece Mh having a cutout portion Mh1 corresponding to the shape of the non-welded region 51F. This forms a welded portion 52D having a narrow region R5. As a result, the area where the welded portion 52D is not formed becomes the non-welded region 51F.

[0087] The present technology has been described above by giving embodiments and their modified examples, but the present technology is not limited to the aspects described in the above embodiments and their modified examples, and various modifications are possible with respect to the present technology.

[0088] For example, in the above-described embodiment and its modified examples, lithium is used as the electrode reactant of the secondary battery, but the type of the electrode reactant is not particularly limited. Specifically, the electrode reactant may be other Group 1 elements in the long periodic table, such as sodium and potassium, or Group 2 elements in the long periodic table, such as magnesium and calcium, or other light metals, such as aluminum.

[0089] The effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0090] The present technology may also be configured as follows: <1> A battery pack including: a battery; and a heat-absorbing member having an endothermic agent and a container for accommodating the endothermic agent, wherein the heat-absorbing member is disposed adjacent to the battery, and the container is provided with a notch. <2> The battery pack according to <1>, wherein the container has an accommodating section for accommodating the endothermic agent and a flange section provided around the accommodating section, and the notch is provided in the flange section. <3> The battery pack according to <2>, wherein the container has a first container part and a second container part, wherein the first container part has a first container portion constituting a part of the container portion and a first flange portion constituting a part of the flange portion, wherein the second container part has a second container portion constituting a part of the container portion and a second flange portion constituting a part of the flange portion, wherein the first container part and the second container part form a container space of the container, wherein the first flange portion and the second flange portion are bonded to each other, and wherein the bonded portions of the first flange portion and the second flange portion have portions where the width of the bonded portions is locally narrowed by the notch. <4> The battery pack according to <3>, wherein the first container part and the second container part are shaped so that the container part is in a substantially triangular prism shape. <5> The battery pack according to <3>, wherein the first container part and the second container part are shaped so that the container part is in a substantially diamond prism shape. <6> The battery pack according to any one of <3> to <5>, wherein the first container part is made of a first sheet material, the first storage portion and the first flange portion are integrally formed by the first sheet material, the second container part is made of a second sheet material, the second storage portion and the second flange portion are integrally formed by the second sheet material, a portion of the first sheet material corresponding to the first flange portion and a portion of the second sheet material corresponding to the second flange portion are bonded to each other, and the notch is formed so as to penetrate the first sheet material and the second sheet material.<7> The battery pack according to any one of <3> to <6>, wherein the adhesive portions of the first flange portion and the second flange portion can be peeled off by heating to allow communication between the storage space of the storage portion and the outside. <8> The battery pack according to any one of <3> to <7>, wherein the first flange portion and the second flange portion are each a laminate including a resin layer, wherein the resin layer of the first flange portion and the resin layer of the second flange portion are welded to each other, and wherein the cutout is formed so as to penetrate the welded portion between the resin layer of the first flange portion and the resin layer of the second flange portion. <9> The battery pack according to any one of <1> to <8>, wherein the battery includes a plurality of the batteries, and wherein the cutout is located adjacent to two adjacent batteries. <10> The battery pack according to <9>, wherein each of the batteries and the heat absorption member is columnar, and wherein the cutout is located in a central region of the heat absorption member in the longitudinal direction of the heat absorption member. <11> A battery pack comprising: a battery; and a heat-absorbing member having a heat-absorbing agent and a container that accommodates the heat-absorbing agent, wherein the heat-absorbing member is disposed adjacent to the battery; and the container has: a container that accommodates the heat-absorbing agent; and a flange portion that is provided around the container and has a peelable portion that can be peeled off by heating to connect an accommodation space of the container to the outside, and the peelable portion has a narrow region where the width of the peelable portion is locally narrower than the width of the flange portion.<12> The flange portion has, at a location adjacent to the narrowed region, a notch, a through-hole, a separable portion that can be separated without heating, or a separable portion that communicates with the storage space. <13> The battery pack according to <11> or <12>, wherein the container has a first container part and a second container part, wherein the first container part has a first storage portion that constitutes a part of the storage portion and a first flange portion that constitutes a part of the flange portion, and the second container part has a second storage portion that constitutes a part of the storage portion and a second flange portion that constitutes a part of the flange portion, and the first storage portion and the second storage portion form a storage space of the storage portion, and the first flange portion and the second flange portion are bonded to each other, and the bonded portion of the first flange portion and the second flange portion corresponds to the peelable portion. <14> The battery pack according to <13>, wherein the first housing portion and the second housing portion are shaped so that the housing portions are substantially triangular prisms. <15> The battery pack according to <13>, wherein the first housing portion and the second housing portion are shaped so that the housing portions are substantially diamond prisms. <16> The battery pack according to any one of <13> to <15>, wherein the first container part is made of a first sheet material, the first storage section and the first flange section are integrally formed by the first sheet material, the second container part is made of a second sheet material, the second storage section and the second flange section are integrally formed by the second sheet material, a portion of the first sheet material corresponding to the first flange section and a portion of the second sheet material corresponding to the second flange section are bonded to each other, and the notch, the through-hole, the separable section, or the separable section is formed adjacent to an adhesive portion of the first sheet material and the second sheet material.<17> The battery pack according to any one of <13> to <16>, wherein the first flange portion and the second flange portion are each a laminate including a resin layer, the resin layer of the first flange portion and the resin layer of the second flange portion are welded to each other, and the notch, the through-hole, the separable portion, or the separated portion is formed adjacent to the welded portion between the resin layer of the first flange portion and the resin layer of the second flange portion. <18> The battery pack according to any one of <11> to <17>, comprising a plurality of the batteries, and the notch, the through-hole, the separable portion, or the separated portion is located adjacent to two adjacent batteries. <19> The battery pack according to <18>, wherein each of the batteries and the heat absorption member is columnar, and the notch, the through-hole, the separable portion, or the separated portion is located in a central region of the heat absorption member in the longitudinal direction of the heat absorption member.

[0091] The effects described in this specification are merely examples, and the effects of the present technology are not limited to the effects described in this specification. Therefore, other effects may be obtained with respect to the present technology.

Claims

1. A battery pack comprising: a battery; and a heat absorbing member having a heat absorbing agent and a container for accommodating the heat absorbing agent, the heat absorbing member being disposed adjacent to the battery; and the container being provided with a notch.

2. The battery pack according to claim 1, wherein the container has a storage section for storing the heat absorbing agent and a flange section provided around the storage section, and the notch is provided in the flange section.

3. The battery pack according to claim 2, wherein the container has a first container part and a second container part, the first container part has a first accommodating portion constituting a part of the accommodating portion and a first flange portion constituting a part of the flange portion, the second container part has a second accommodating portion constituting a part of the accommodating portion and a second flange portion constituting a part of the flange portion, an accommodating space of the accommodating portion is formed by the first accommodating portion and the second accommodating portion, the first flange portion and the second flange portion are bonded to each other, and the bonded portions of the first flange portion and the second flange portion have a portion where the width of the bonded portion is locally narrowed by the notch.

4. The battery pack according to claim 3, wherein the first storage section and the second storage section are shaped so that the storage section is substantially in the shape of a triangular prism.

5. The battery pack according to claim 3, wherein the first storage section and the second storage section are shaped so that the storage section is in the shape of a generally diamond-shaped column.

6. A battery pack as claimed in any one of claims 3 to 5, wherein the first container part is made of a first sheet material, the first storage portion and the first flange portion are integrally formed by the first sheet material, the second container part is made of a second sheet material, the second storage portion and the second flange portion are integrally formed by the second sheet material, a portion of the first sheet material corresponding to the first flange portion and a portion of the second sheet material corresponding to the second flange portion are bonded to each other, and the cutout is formed so as to penetrate the first sheet material and the second sheet material.

7. A battery pack as claimed in any one of claims 3 to 6, wherein the adhesive portions of the first flange portion and the second flange portion can be peeled off by heating to connect the storage space of the storage portion to the outside.

8. A battery pack as claimed in any one of claims 3 to 7, wherein the first flange portion and the second flange portion are each a laminate including a resin layer, the resin layer of the first flange portion and the resin layer of the second flange portion are welded to each other, and the notch is formed so as to penetrate the welded portion between the resin layer of the first flange portion and the resin layer of the second flange portion.

9. The battery pack according to any one of claims 1 to 8, comprising a plurality of the batteries, and wherein the cutouts are arranged at positions adjacent to two of the batteries that are adjacent to each other.

10. The battery pack according to claim 9, wherein each of the batteries and the heat absorbing member is columnar, and the notch is disposed in a central region of the heat absorbing member in the longitudinal direction of the heat absorbing member.

11. A battery pack comprising: a battery; and a heat absorbing member having a heat absorbing agent and a container for accommodating the heat absorbing agent, the heat absorbing member being disposed adjacent to the battery, the container having a storage section for accommodating the heat absorbing agent, and a flange section provided around the storage section and having a peelable section that can be peeled off by heating to connect the storage space of the storage section to the outside, the peelable section having a narrow region where the width of the peelable section is locally narrower than the width of the flange section.

12. The battery pack according to claim 11, wherein the flange portion has, adjacent to the narrow area, a notch, a through hole, a separable portion that can be separated without heating, or a separable portion that communicates with the storage space.

13. A battery pack as described in claim 11 or 12, wherein the container has a first container part and a second container part, the first container part has a first accommodating portion that constitutes a part of the accommodating portion and a first flange portion that constitutes a part of the flange portion, the second container part has a second accommodating portion that constitutes a part of the accommodating portion and a second flange portion that constitutes a part of the flange portion, an accommodating space of the accommodating portion is formed by the first accommodating portion and the second accommodating portion, the first flange portion and the second flange portion are bonded to each other, and the bonded portions of the first flange portion and the second flange portion correspond to the peelable portion.

14. The battery pack according to claim 13, wherein the first storage section and the second storage section are shaped such that the storage section is substantially in the shape of a triangular prism.

15. The battery pack according to claim 13, wherein the first housing portion and the second housing portion are shaped such that the housing portion is generally in the shape of a diamond prism.

16. A battery pack as claimed in any one of claims 13 to 15, wherein the first container part is made of a first sheet material, the first accommodating portion and the first flange portion are integrally formed by the first sheet material, the second container part is made of a second sheet material, the second accommodating portion and the second flange portion are integrally formed by the second sheet material, a portion of the first sheet material corresponding to the first flange portion and a portion of the second sheet material corresponding to the second flange portion are bonded to each other, and the notch, the through hole, the separable portion or the separable portion is formed adjacent to the bonded portion of the first sheet material and the second sheet material.

17. A battery pack as described in any one of claims 13 to 16, wherein the first flange portion and the second flange portion are each a laminate including a resin layer, the resin layer of the first flange portion and the resin layer of the second flange portion are welded to each other, and the notch, the through hole, the separable portion or the separable portion is formed adjacent to the welded portion between the resin layer of the first flange portion and the resin layer of the second flange portion.

18. A battery pack as described in any one of claims 11 to 17, comprising a plurality of the batteries, and wherein the notch, the through hole, the separable portion, or the separation portion is arranged in a position adjacent to two adjacent batteries.

19. A battery pack as described in claim 18, wherein each of the batteries and the heat absorption member is columnar, and the notch, the through hole, the detachable portion, or the detachable portion is disposed in a central region of the heat absorption member in the longitudinal direction of the heat absorption member.

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